Diseases
Leaf spots of Asian pear
Pyrus pyrifolia (Burm. f.) Nakai
A complex of diseases manifesting as necrotic spots on the leaf blade, the most significant of which is black spot, caused by a specific pathotype of Alternaria alternata.
In the reference 5 varieties crop Japanese pear, where this is mentioned in the description.
The main disease of this group is black spot, caused by the 'pear pathotype' of the fungus Alternaria alternata, also known as Alternaria gaisen. The pathogen produces AK-toxin, which specifically infects Pyrus pyrifolia and other Asian species, causing dark brown or black spots, necrosis, and premature defoliation. Susceptibility to this disease is genetically determined and linked to the dominant susceptibility loci Aki, Ani, and Ana.
In addition to black spot, bacterial spot caused by Erwinia pyrifoliae is observed in this crop, which is characterized by black-brown streaks on the veins and necrotic spots. The pathological process can also be triggered by fungal infections such as Entomosporium leaf spot (Diplocarpon mespili) and anthracnose (Colletotrichum fructicola), the latter of which is capable of causing both small black spots and extensive tissue lesions, leading to the loss of foliage.
General information about the subject — on the page Leaf spot diseases.
Varieties of Japanese pear mentioned in the description
Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.
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